Mesoporous Structure of Hydrous Tin(IV) Oxide Coprecipitated with Aluminum Cations

The changes produced in the mesoporous structure of hydrous tin(IV) oxide by coprecipitated aluminum cations and the possibility of creating a uniform mesoporosity were evaluated from the average pore radius, mesopore size distribution, and shape of the hysteresis loops in CCl4 adsorption–desorption isotherms. The results demonstrate that the coprecipitated aluminum cations reduce the average pore radius, change the shape of the mesopores (from cylindrical to bottle-shaped), and stabilize a uniform mesoporous structure with a narrow neck radius distribution. Increasing the Al : Sn molar ratio to above 0.15 reduces the predominant mesopore radius, corresponding to the peak in the distribution curve, from 6.2 to 2.4 nm. The materials with very narrow pore radius distributions can be regarded as mesoporous molecular sieves with a calibrated pore radius of 4.1 nm.